In the sport of archery, the basic configuration and operation of compound bows are generally known as they have been in use for a long time. Compound bows are used a great deal in hunting because they provide several advantages over the simpler non-compound varieties.
Compound archery bows include tension cables and a bowstring that are connected between upper and lower bow limbs. It is customary to dispose the bowstring and the tension cables relatively close together, proximate the vertical centerline of the bow, in order to minimize any twisting torque on the bow limbs.
A notable advantage of compound bows is that a reduction in draw weight is realized, allowing the archer to hold full draw at a draw weight less than that of the required maximum.
Compound bows also achieve more gradual arrow acceleration upon release with reduced stress on the arrow and the archer, resulting in increased arrow speed and shooting accuracy.
A problem presented by compound bows is that noise is generated upon releasing the bowstring to propel the arrow. When the bowstring reaches the end of its arrow-propelling path, the cables (which cross in the center portion of the bow), rub against each other. This rubbing causes frictional forces that may produce cable wear and create noise which may alert game birds and animals.
A popular solution to this problem is to provide compound bows with a cable guard having a rod mount that can provide a selectable degree of displacement of the tension cable from the plane of the path of the bowstring, by rotation of the mount. The rod mount is generally threaded directly into the bow handle area, either above or below the handgrip.
The prior art shows that numerous attempts have been made to maintain the lateral spacing of the cables while reducing the friction between the cables.
U.S. Pat. No. 4,452,222 entitled “Cable Guard for a Compound Bow” to Quartino et al. discloses a cable guard that comprises a rod that extends from the bow handle and beyond the cables when the bow is in a fully drawn position. The rod is positioned laterally from the bowstring to avoid any interference with the bowstring. A cable-retaining member is rotatably and slidably mounted on the rod. The cable-retaining member includes two bores that are perpendicular to the rod for slidably receiving the cables to hold them in a lateral spaced relationship with the bowstring.
U.S. Pat. No. 4,596,228 entitled “Cable Separator for Compound Bows” to Smith discloses a rod attached to the handle portion of the bow that extends rearwardly beyond the bowstring. Positioned about the external surface of the rod is a cable guard assembly which positions a cable on either side of the bow. The purpose of the invention is to prevent an interfering contact of the cable strands with an arrow during impelling flight of the arrow from the bow, thereby obviating impairment of the true flight of the arrow released from the bow.
U.S. Pat. No. 5,718,213, entitled “Swing Arm Cable Guard” to Gallops Jr. et al., discloses a cable guard, including a support member and a swing arm pivotally connected thereto. A cable retaining means having two bores therein for retaining the cables is pivotally mounted on the swing arm. The angle between the support member and the swing arm is such that when the bow is drawn, the distance between the cables, which is contained in the cable retaining means, and the plane of the bowstring travel, is less than the distance between the cables and the plane of bowstring travel when the bow is at rest. Because the cables are closer to the plane of bowstring travel when the bow is drawn, the cables and bow limbs are less stressed when the bow is drawn. The cable guard retaining means may not be adjusted to change the distance between the cable guard retaining means and bowstring.
In the prior art for cable guards of the type described above, the rod on which the retaining members were slidably mounted was required to be of sufficient length to permit the retaining members to be mounted thereon when the bow was in the drawn condition.
Unfortunately, the rod length can be a potential distraction to the archer when the arrow is being shot. Another problem presented by the rod of the prior art is that most archers do not remove the cable guard from their bow for transport, and because many forms of transportation require bows to be cased for transport, the use of such cable guards requires substantial storage area and larger bow cases.
Further, the rod and sliding retainer introduces additional friction into the system, for example, the increased friction force between the cables and the sliding retainer and between the sliding retainer and the support rod as the bowstring is moved from brace position to full draw.
Some of these disadvantages appear to have been overcome by the cable guard disclosed in U.S. Pat. No. 4,834,061 entitled “Cable Vibraguard” to the present inventor, in which a support member has a swing arm pivotally attached thereto. A cable retaining member having two openings therein is located at the free end of the swing arm. The cables pass through and are contained within the openings of the retaining member. When the bow is drawn, the cables travel in a plane parallel to the general direction of the bowstring and cause the retaining member and connected swing arm to be pivoted away from the support member and the bow handle. The present invention is an improvement of the cable guard disclosed in this patent.
The present invention concerns another means for reducing the frictional forces between the cables and the bores of the retaining means.
Another problem presented by a conventional compound bow is that a considerable amount of energy stored in bow limb is wasted by propelling the bow limb forward when the drawn bowstring is released. Instead, it is desirable to use at least a portion of this wasted energy to propel an arrow.
The arrow speed depends upon several factors, one of the most important being the amount of energy put into the bow. Generally speaking, the more total energy put into the bow, the faster that the arrow will be propelled. Increased arrow speed is desirable, especially when hunting and shooting heavy arrows.
Another problem presented by a conventional compound bow is that the crossing cables are located in the point of view of the archer, thus diminishing the visibility of the archer.
Thus, the present inventor feels the necessity of providing a cable guard for a compound bow that is simple, quiet, inexpensive, and less susceptible to wear and tear, increases the visibility for the archer, and, at the same time, increases the arrow speed.